There exist many problems such as inefficient coagulant more expensive treatment the secondary pollution in treating drilling waste water.

钻井污水处理中存在着混凝剂效力不高，处理费用较高并易造成二次污染等问题。

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The smooth tie-back of pre-drilled wells proves that Pinghu drilling template and all secondary structures for the tie-back are very successful.

平湖油气田预钻井顺利回接的实践证明，平湖钻井基盘和回接辅助结构技术是非常成功的。

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Since 1995, the secondary infill drilling adjustment has been carried out in this area.

从1995年开始又对该区块进行了二次加密调整。

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Unless preps are near state grammar schools and hence have a secure niche drilling children for the 11-plus exams, they may seek to merge with secondary schools, which can then market an all-through education insulated from the vicissitudes of competitive entry at 11 or 13 years of age.

ECONOMIST: Selling schooling in a downturn